1. Field of the Invention
This invention relates generally to structures having superhydrophobic surfaces, and processes for their fabrication.
2. Related Art
Hydrophobic structures are known for their ability to repel high surface tension liquids such as water. Some hydrophobic structures have been made that include a plurality of raised features that are spaced apart by interstices and held in positions relative to each other on a substrate. These raised features may take the form of various shapes, including posts, blades, spikes, and ridges. When a liquid having a sufficiently high surface tension makes contact with the surface of such a hydrophobic structure, the liquid may form an interface with the surface of the hydrophobic structure at a local contact angle sufficiently high so that the liquid does not immediately penetrate into the interstices. Such a surface is then described as being “superhydrophobic”.
Despite these developments, superhydrophobic surfaces formed on raised features often require careful attention to maintaining a low pressure applied to the raised features by the liquid, to delay breakdown of the superhydrophobic repelling force and resultant penetration of the liquid through the surface and into the interstices between the raised features. The requirement of such a low pressure may prevent utilization of such superhydrophobic surfaces in environments where a fluid needs to flow over the surfaces, because such a flow may generate significant pressure on the surfaces. Moreover, superhydrophobic surface behavior has been explored for a limited scope of end use applications. Expansion of such end uses may facilitate new ways of handling liquids.
There accordingly is a continuing need for new types of superhydrophobic surface structures that make feasible the exploitation of superhydrophobic surface behavior.